exam1sp2009f3 - General Chemistry I Examination 1

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Unformatted text preview: General Chemistry I Examination 1 Name___________________________________ R. Lopez de la Vega form 3 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Calculate the atomic mass of element ʺXʺ, if it has 2 naturally occurring isotopes with the following masses and natural abundances: X- 45 X- 47 44.8776 amu 46.9443 amu 32.88% 67.12% C) 45.91 amu D) 44.99 amu E) 46.27 amu 2) 1) A) 46.34 amu B) 46.84 amu 2) A substance composed of 2 or more elements in a fixed, definite proportion is considered A) an alloy. B) a heterogeneous mixture. C) a solution. D) a compound. E) a homogeneous mixture. 3) Determine the volume of hexane that contains 5.33 × 1022 molecules of hexane. The density of hexane is 0.6548 g/mL and its molar mass is 86.17 g/mol. A) 8.59 mL B) 12.4 mL C) 13.5 mL D) 11.7 mL E) 7.40 mL 4) Which of the following statements about energy is FALSE? A) The total energy of a system remains constant. B) Systems tend to change in order to lower their potential energy. C) Energy can be converted from one type to another. D) Potential energy is associated with the motion of particles. E) Energy is the capacity to do work. 5) Determine the number of protons, neutrons and electrons in the following: 65 X 29 A) p+ = 29 B) p+ = 36 C) p+ = 36 D) p+ = 29 E) p+ = 29 n° = 36 n° = 36 n° = 29 n° = 36 n° = 29 e- = 36 e- = 29 e- = 36 e- = 29 e- = 36 3) 4) 5) 6) How many xenon atoms are contained in 2.36 moles of xenon? A) 7.91 × 1025 xenon atoms B) 3.92 × 1024 xenon atoms C) 1.87 × 1026 xenon atoms D) 2.55 × 1023 xenon atoms E) 1.42 × 1024 xenon atoms 7) How many significant figures are in the measurement, 0.0005890 g? A) 4 B) 5 C) 6 D) 7 C‐1 6) 7) E) 8 form 3 8) Predict the charge that an aluminum ion would have. A) 1 B) 1+ C) 2+ 8) D) 5 E) 3+ 9) 9) A 14.01 g sample of N 2 reacts with 3.02 g of H 2 to form ammonia (NH3 ). If ammonia is the only product, what mass of ammonia is formed? A) 14.01 g B) 17.03 g C) 1.10 g 10) Choose the heterogeneous mixture from the list below. A) carbon (graphite) B) chlorine gas C) chicken noodle soup D) black coffee E) gatorade 11) Which of the following statements about subatomic particles is TRUE? A) Electrons make up most of the mass of an atom. B) A neutral atom contains the same number of protons and electrons. C) Neutrons and electrons are found in the nucleus of an atom. D) Protons have about the same mass as electrons. E) Protons and neutrons have opposite, but equal in magnitude, charges. 12) Predict the charge that the ion formed from bromine would have. A) 2+ B) 1+ C) 1 D) 2 D) 3.02 g E) 23.07 g 10) 11) 12) E) 4+ 13) 13) A student performs an experiment to determine the density of a sugar solution. She obtains the following results: 4.71 g/mL, 4.73 g/mL, 4.67 g/mL, 4.69 g/mL. If the actual value for the density of the sugar solution is 4.40 g/mL, which statement below best describes her results? A) Her results are precise, but not accurate. B) Her results are both precise and accurate C) Her results are accurate, but not precise. D) Her results are neither precise nor accurate. E) It isnʹt possible to determine with the information given. 14) Calculate the mass (in ng) of 2.33 x 10 20 atoms of oxygen. A) 4.69 × 107 ng B) 1.62 × 107 ng C) 3.73 × 106 ng D) 2.25 × 103 ng E) 6.19 × 106 ng 15) What mass (in kg) does 5.84 moles of titanium (Ti)have? A) 0.820 kg B) 0.632 kg C) 0.352 kg 14) 15) D) 0.122 kg E) 0.280 kg C‐2 form 3 16) What does ʺXʺ represent in the following symbol? 30 X 14 A) zinc B) nickel C) sulfur D) silicon E) ruthenium 17) How many moles of C 3 H8 contain 4.95 × 1024 hydrogen atoms? A) 8.22 moles C 3 H8 B) 3.09 moles C 3 H8 C) 9.73 moles C 3 H8 D) 6.58 moles C 3 H8 E) 1.03 moles C 3 H8 18) Calculate the molar mass for Mg(ClO4 )2 . A) 119.52 g/mol B) 247.52 g/mol C) 75.76 g/mol D) 123.76 g/mol E) 223.21 g/mol 19) Determine the empirical formula for a compound that contains C, H and O. It contains 52.14% C and 34.73% O by mass. A) C2 H6 O B) CHO C) CH4 O3 D) CH3 O E) C4 H13O2 20) How many moles of Cs are contained in 595 kg of Cs? A) 1.26 × 103 moles Cs B) 4.48 × 103 moles Cs C) 7.91 × 104 moles Cs D) 2.23 × 102 moles Cs E) 5.39 × 102 moles Cs 21) Which of the following elements is an alkaline earth metal? A) Cu B) Mg C) Ti 16) 17) 18) 19) 20) 21) D) Cs E) Br 22) 22) How many sodium ions are contained in 99.6 mg of Na 2 SO3 ? The molar mass of Na2 SO3 is 126.05 g/mol. A) 2.10 × 1021 sodium ions B) 4.76 × 1020 sodium ions C) 1.05 × 1021 sodium ions D) 1.52 × 1027 sodium ions E) 9.52 × 1020 sodium ions C‐3 form 3 23) Which of the following represents a chemical property of hydrogen gas? A) It is gaseous at room temperature. B) It reacts explosively with oxygen. C) It is less dense than air. D) It is colorless. E) It is tasteless. 24) Determine the name for H 2 CO 3 . A) carbonous acid B) dihydrogen carbonate C) carbonic acid D) hydrocarbonic acid E) hydrocarbide acid 25) The form number designated at the top of my exam is A) form I B) form II C) form III 23) 24) 25) D) form IV E) form V C‐4 Answer Key Testname: EXAM1SP2009 1) E 2) D 3) D 4) D 5) D 6) E 7) A 8) E 9) B 10) C 11) B 12) C 13) A 14) E 15) E 16) D 17) E 18) E 19) A 20) B 21) B 22) E 23) B 24) C 25) No Correct Answer Was Provided. C‐5 ...
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This note was uploaded on 02/12/2011 for the course CHEM 112 taught by Professor Sttaf during the Spring '03 term at Arkansas Pine Bluff.

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